Machine tools are increasingly designed for use with a number of tool heads which are sequentially mounted on the machine tool as required. There is therefore a clear requirement that the tool heads be readily available for use. Each tool head comprises a tool holder designed to be mounted in a machine tool spindle. In each tool holder there is mounted an appropriate cutting tool which is locked in position by a tool locking member such as a locking nut or ring. Ready and rapid replacement of the cutting tools is clearly a prerequisite for achieving an uninterrupted supply of tool heads for use as required.
Hitherto, the replacement of the cutting tools in the tool holders has been effected manually by the manual loosening, by means of an appropriate wrench, of the tool locking member, the removal of the cutting tool and its replacement by another cutting tool, and the subsequent tightening of the locking member so as to retain the cutting tool securely in position in the tool holder. Clearly, such a manual regime is very time consuming. In addition, the manual tightening of the tool locking member carries with it the consequence that differing tool heads may have the cutting tools secured therein to differing extents as a result of differing degrees of tightening being imparted to the locking members.
There have been various prior proposals for the provision of power wrenches or otherwise to mechanize tool changing in machine tools (e.g. U.S. Pat. Nos. 3,380,324; 3,797,335), but in general they have been of relatively cumbersome, complicated construction.
It is an object of the present invention to provide a new and improved mechanized tool locking and releasing device in which the above-referred-to disadvantages are substantially reduced or overcome.